202 research outputs found

    Weather and Management Impact on Crop Yield Variability in Rotations

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    Crop rotations are designed to increase productivity and reduce costs. These advantages are contingent upon favorable weather and require appropriate management. Unpredictable weather poses risks to dryland crop production. Information on how weather affects yields in different cropping systems and how farmers could respond with management would help minimize risk and stabilize yield and income. We evaluated the effects of preseason and growing season weather variability on continuous and sequential cropping of corn, sorghum, and soybean in a 12-yr span, and suggest how management decisions could influence cropping system performance. Models of different levels of sophistication have been developed to link yields of individual crops with weather factors. But there is a paucity of information on how weather and management affect yields in whole cropping systems. Furthermore, many models demand a large amount of input data, which is a major limitation to routine application by potential users. This study developed simple empirical models to relate yield and management with a combined index of composite weather variables in whole cropping systems. The study was conducted from 1984 to 1995 at the Agricultural Research and Development Center near Mead, NE. Correlation and regression analyses were used to relate system performance to weather. Yield was the dependent variable and several combined indices of weather factors were predictor variables. The combined indices of weather or composite weather variables were biological windows (BW) and standardized precipitation index (SPI). Biological windows represent the time during the entire year during which rainfall and air temperature favor biological activities. The biological windows are derived from the mean monthly precipitation and temperature data. The SPI is the difference of precipitation from the long-term average (\u3e30 yr) divided by the standard deviation, a measure used to determine how wet or dry a period of time is compared with average weather patterns, up to a certain date. Both BW and SPI are calculated with simple computer programs. Standard deviation was used as a measure of yield/income variability. Weather effects on yield and income fluctuations of the cropping systems are discussed, along with potentials for the farmer to influence this variability through management

    Imputation of missing count data of recreational boat retrievals from remote camera surveys in the Perth Metropolitan region, Western Australia

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    In Western Australia (WA), remote cameras have been used to monitor boating activity at boat ramps since 2006 to assist in ongoing recreational fishing surveys. These monitoring schemes are useful tools to validate boating activity (defined here as the number of retrievals) and to corroborate estimates of recreational fishing effort obtained from other surveys. This is because remote cameras (also referred to as digital cameras) can provide complete coverage (i.e. 24 hours, 365 days) of boating activities

    Analysis of thermal-hydraulic transients for the Miniature Neutron Source Reactor (MNSR) in Ghana

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    Abstract: A mathematical model is presented that permits to simulate the effect of the cooling coils of the pool upper section on the reactor thermal-hydraulic behaviour of Ghana research reactor-1. The model is based on a lumped parameter description solved numerically using Matlab/Simulink tool which is a commercial software package with the capability of modelling dynamical and control systems. The model incorporates fuel grids and cooling coil models as well as radiating energy from the clad. In this model, the reactor tank and the pool is divided into three sections. The model predictions are qualified by comparing the results with experimental data. The effect of cooling the upper section of the pool on reactor thermal-hydraulic parameters using the cooling coil is presented and discussed. It was observed that all maximum values of the reactor thermalhydraulic parameters decrease when the cooling coil power is increased. Good agreement is found between the model predictions and the experimental results

    Equitable global value chain and production network as a driver for enhanced sustainability in developing economies

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    Recent studies on the global value chain (GVC) have highlighted the need to better integrate the value chains of developing countries of the global South with that of the global North regions, which are more highly developed. This is aimed at enhancing the economic and social sustainable upgrading of the value chains of the global South regions. The paper thus seeks to answer a critical question as to whether the existing GVC set-up pertaining to global North and South countries is equitable and whether it would yield the needed socio-economic and wider sustainable benefits, particularly to global South countries. a conceptual Global Value Chain (GVC) model is developed based on the economy-wide and system-based Multi-Regional Input–Output methodology to achieve this goal. Subsequently, this was empirically tested to measure embodied flows in capital and labour for sustainable development between global North and South regions. These are achieved using the GVC networks of the UK (from the global North) and some countries in sub Saharan Africa (from the global South) to exemplify these developments. With implications for equitable, sustainable development, our study shows significant imbalances exist in the flows of value added activities from the global South to the global North, particularly in the primary industries, which produce low-value products in their raw state. Subsequently, this creates a disproportionate economic disadvantage for South countries. As such, if global South countries are to fully benefit from GVC, the study shows that these imbalances must be addressed, such as through structural changes in the economies of global South countries from their dependencies on the primary industries

    Cardiometabolic syndrome among general adult population in Ghana: The role of lipid accumulation product, waist circumference-triglyceride index, and triglyceride-glucose index as surrogate indicators

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    Background: Visceral obesity and insulin resistance contribute to developing cardiometabolic syndrome (MetS). We investigated the predictive abilities of lipid accumulation product (LAP), waist circumference-triglyceride index (WTI), and triglyceride-glucose (TyG) index for MetS screening among the general Ghanaian adults. Methods: The final prospective analysis included 4740 healthy adults aged 30–90 years from three communities comprising Ejisu, Konongo, and Ashanti Akim Agogo in Ghana. Self-structured questionnaire pretested was used to collect sociodemographic, anthropometric, and clinical data. Blood samples were taken after fasting to measure glucose and lipid levels. LAP, WTI, and TyG were calculated from standard equations. MetS was defined by the International Diabetes Federation criteria. Receiver operating characteristic (ROC) curves and multivariable logistic regression were utilized to evaluate the potential of the three indices in identifying MetS. Results: Of the 4740 participants, 39.7% had MetS. MetS was more common in females (50.3%) than in males (22.2%). Overall, LAP ≥ 27.52 yielded as the best index for MetS with the highest area under the ROC curve (AUC) (0.866). At cut-off LAP point of ≥ 23.87 in males and ≥ 33.32 in females, an AUC of 0.951 and 0.790 was identified in MetS prediction, respectively. LAP was an independent risk measure of MetS for both males (45.6-fold) and females (3.7-fold) whereas TyG was an independent risk measure for females (3.7-fold) only. Conclusions: MetS is increasing among the general adult population. LAP and TyG are important sex-specific risk measures to screen for MetS among the general adult population in our cohort

    Modes of carbon fixation in an arsenic and CO<sub>2</sub>-rich shallow hydrothermal ecosystem

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    Abstract The seafloor sediments of Spathi Bay, Milos Island, Greece, are part of the largest arsenic-CO2-rich shallow submarine hydrothermal ecosystem on Earth. Here, white and brown deposits cap chemically distinct sediments with varying hydrothermal influence. All sediments contain abundant genes for autotrophic carbon fixation used in the Calvin-Benson-Bassham (CBB) and reverse tricaboxylic acid (rTCA) cycles. Both forms of RuBisCO, together with ATP citrate lyase genes in the rTCA cycle, increase with distance from the active hydrothermal centres and decrease with sediment depth. Clustering of RuBisCO Form II with a highly prevalent Zetaproteobacteria 16S rRNA gene density infers that iron-oxidizing bacteria contribute significantly to the sediment CBB cycle gene content. Three clusters form from different microbial guilds, each one encompassing one gene involved in CO2 fixation, aside from sulfate reduction. Our study suggests that the microbially mediated CBB cycle drives carbon fixation in the Spathi Bay sediments that are characterized by diffuse hydrothermal activity, high CO2, As emissions and chemically reduced fluids. This study highlights the breadth of conditions influencing the biogeochemistry in shallow CO2-rich hydrothermal systems and the importance of coupling highly specific process indicators to elucidate the complexity of carbon cycling in these ecosystems

    Unrecognized hypertension among a general adult Ghanaian population: An urban community-based cross-sectional study of prevalence and putative risk factors of lifestyle and obesity indices

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    Hypertension (HTN) is the leading cause of cardiovascular diseases. Nevertheless, most individuals in developing countries are unaware of their blood pressure status. We determined the prevalence of unrecognized hypertension and its association with lifestyle factors and new obesity indices among the adult population. This community-based study was conducted among 1288 apparently healthy adults aged 18–80 years in the Ablekuma North Municipality, Ghana. Sociodemographic, lifestyle characteristics, blood pressure and anthropometric indices were obtained. The prevalence of unrecognized HTN was 18.4% (237 / 1288). The age groups 45–54 years [aOR = 2.29, 95% CI (1.33–3.95), p = 0.003] and 55–79 years [aOR = 3.25, 95% CI (1.61–6.54), p = 0.001], being divorced [aOR = 3.02 95% CI (1.33–6.90), p = 0.008], weekly [aOR = 4.10, 95% CI (1.77–9.51), p = 0.001] and daily alcohol intake [aOR = 5.62, 95% CI (1.26–12.236), p = 0.028] and no exercise or at most once a week [aOR = 2.25, 95% CI (1.56–3.66), p = 0.001] were independently associated with HTN. Among males, the fourth quartile (Q4) of both body roundness index (BRI) and waist to height ratio (WHtR) [aOR = 5.19, 95% CI (1.05–25.50), p = 0.043] were independent determinants of unrecognized HTN. Among females, the third quartile (Q3) [aOR = 7.96, 95% CI (1.51–42.52), p = 0.015] and Q4 [aOR = 9.87 95% CI (1.92–53.31), p = 0.007] of abdominal volume index (AVI), the Q3 of both BRI and WHtR [aOR = 6.07, 95% CI (1.05–34.94), p = 0.044] and Q4 of both BRI and WHtR [aOR = 9.76, 95% CI (1.74–54.96), p = 0.010] were independent risk factors of HTN. Overall, BRI (AUC = 0.724) and WHtR (AUC = 0.724) for males and AVI (AUC = 0.728), WHtR (AUC = 0.703) and BRI (AUC = 0.703) for females yielded a better discriminatory power for predicting unrecognized HTN. Unrecognized hypertension is common among the apparently healthy adults. Increased awareness of its risk factors, screening, and promoting lifestyle modification is needed to prevent the onset of hypertension

    Prevalence of preeclampsia and algorithm of adverse foeto-maternal risk factors among pregnant women in the central region of Ghana: A multicentre prospective cross-sectional study

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    Background: Preeclampsia is a leading cause of foeto-maternal deaths especially in Sub-Saharan Africa. However, the prevalence and risk factors of preeclampsia are scarce in the Central region of Ghana with previous study assessing individual independent risk factors. This study determined the prevalence and algorithm of adverse foeto-maternal risk factors of preeclampsia. Methods: This multi-centre prospective cross-sectional study was conducted from October 2021 to October 2022 at the Mercy Women’s Catholic Hospital and Fynba Health Centre in Central region, Ghana. A total of 1,259 pregnant women were randomly sampled and their sociodemographic, clinical history, obstetrics and labour outcomes were recorded. Logistic regression analysis using SPSS version 26 was performed to identify risk factors of preeclampsia. Results: Of the 1,259 pregnant women, 1174 were finally included in the study. The prevalence of preeclampsia was 8.8% (103/1174). Preeclampsia was common among 20–29 years age group, those who had completed basic education, had informal occupation, multigravida and multiparous. Being primigravida [aOR = 1.95, 95% CI (1.03–3.71), p = 0.042], having previous history of caesarean section [aOR = 4.48, 95% CI (2.89–6.93), p \u3c 0.001], foetal growth restriction [aOR = 3.42, 95% CI (1.72–6.77), p \u3c 0.001] and birth asphyxia [aOR = 27.14, 95% CI (1.80–409.83), p = 0.017] were the independent risk factors of preeclampsia. Pregnant women exhibiting a combination of primigravida, previous caesarean section and foetal growth restriction were the highest risk for preeclampsia [aOR = 39.42, 95% CI (8.88–175.07, p \u3c 0.001] compared to having either two or one of these factors. Conclusion: Preeclampsia is increasing among pregnant women in the Central region of Ghana. Pregnant women being primigravida with foetal growth restriction and previous history of caesarean section are the highest risk population likely to develop preeclampsia with neonates more likely to suffer adverse birth outcome such as birth asphyxia. Targeted preventive measures of preeclampsia should be created for pregnant women co-existing with multiple risk factors

    Association between micronutrients, oxidative stress biomarkers and angiogenic growth mediators in early and late-onset preeclamptic Ghanaian women

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    Objectives: Micronutrients, especially calcium (Ca) and magnesium (Mg) are reported to reduce preeclampsia events via several factors such as endothelial cell control, optimal oxidative stress and a balanced angiogenic growth mediator. We evaluated the association of micronutrients with oxidative stress biomarkers, and angiogenic growth mediators in early-onset preeclampsia and late-onset preeclampsia. Methods: This case-control study recruited 197 preeclampsia (early-onset preeclampsia = 70 and late-onset preeclampsia = 127) as cases and 301 normotensive pregnant women as controls from the Komfo Anokye Teaching Hospital, Ghana. Samples were collected after 20 weeks of gestation for both cases and controls and estimated for Ca, Mg, soluble fms-like tyrosine kinase-1, placental growth factor, vascular endothelial growth factor-A, soluble endoglin, 8-hydroxydeoxyguanosine, 8-epiprostaglandinF2-alpha and total antioxidant capacity. Results: Early-onset preeclampsia women had significantly lower levels of Ca, Mg, placental growth factor, vascular endothelial growth factor-A and total antioxidant capacity but higher levels of soluble fms-like tyrosine kinase-1, soluble endoglin, 8-epiprostaglandinF2-alpha, 8-hydroxydeoxyguanosine, soluble fms-like tyrosine kinase-1/placental growth factor ratio, 8-epiprostaglandinF2-alpha /placental growth factor ratio, 8-hydroxydeoxyguanosine/placental growth factor ratio and soluble endoglin/placental growth factor ratio than late-onset preeclampsia and normotensive pregnant women (p \u3c 0.0001). Among the early-onset preeclampsia women, the first and second quartile for serum placental growth factor, first quartile for vascular endothelial growth factor-A and total antioxidant capacity and the fourth quartiles for serum sEng, serum sFlt-1, 8-epiPGF2 and 8-OHdG were independently associated with low Ca and Mg (p \u3c 0.05). Among late-onset preeclampsia women, the fourth quartile for soluble fms-like tyrosine kinase-1 was independently associated with low Ca and Mg (p \u3c 0.05). Conclusion: Magnesium and calcium are associated with an imbalance in angiogenic growth mediators and oxidative stress biomarkers among preeclampsia women, particularly early-onset preeclampsia. Serial and routine measurement of these micronutrients would allow the monitoring of poor placental angiogenesis while enabling an understanding of the triggers of increased oxidative stress and reduced antioxidant in preeclampsia
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